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Publication numberUS4463305 A
Publication typeGrant
Application numberUS 06/331,115
Publication dateJul 31, 1984
Filing dateDec 16, 1981
Priority dateDec 16, 1981
Fee statusPaid
Also published asCA1211186A, CA1211186A1, DE3246322A1, DE3246322C2
Publication number06331115, 331115, US 4463305 A, US 4463305A, US-A-4463305, US4463305 A, US4463305A
InventorsRichard J. Wineland, Robert L. Gault
Original AssigneeFord Motor Company
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Alternator load shedder for engine starting improvement
US 4463305 A
Abstract
A method and system for delaying mechanical loading of an internal combustion engine by an alternator during start-up and transitional phases of the engine by inhibiting the field winding current of the alternator until the engine reaches a predetermined operational condition for a continuous predetermined period of time.
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Claims(8)
We claim:
1. A system, within an electrical starting system for an internal combustion engine, for preventing mechanical loading by an engine driven alternator until said engine operates at least in its idle condition for a finite predetermined period of time comprising:
means connected to said engine for sensing the operational condition of said engine and producing an output when said engine maintains its idle condition for a predetermined finite period of time;
means connected to said sensing means for inhibiting the field current in said alternator in the absence of said output from said sensing means and for allowing normal field current to flow in said alternator when said output is produced.
2. A system as in claim 1, wherein said electrical starting system includes a primary source of electrical energy;
switching means for separately connecting and disconnecting said primary source to a plurality of defined circuits;
means within a first defined circuit for starting said automotive engine when said switching means connects said primary source to said first circuit;
said sensing means being within a second defined circuit and producing said output by interconnecting said primary source to said inhibiting means when said switching means connects said primary source to said second defined circuit and after said engine idle condition is reached for said predetermined finite period of time; and
said inhibiting means includes a first voltage responsive switch which closes the field current line to said alternator when said output is produced by said sensing means.
3. A system as in claim 2, wherein said inhibiting means also includes a second voltage responsive switch which holds both said voltage responsive switches closed when said output is produced by said sensing means, until said switching means disconnects said primary source.
4. A system as in claim 1, wherein said sensing means monitors the vacuum level within said engine and includes a normally open vacuum responsive switch which is closed after said vacuum level exceeds a predetermined value for said predetermined finite period of time.
5. A system as in claim 4, wherein said electrical starting system includes a primary source of electrical energy;
switching means for separately connecting and disconnecting said primary source to a plurality of defined circuits;
means within a first defined circuit for starting said automotive engine when said switching means connects said primary source to said first circuit;
said sensing means being within a second defined circuit which produces said output by interconnecting said primary source of electrical energy to said inhibiting means after said switching means connects said primary source to said second circuit and said engine idle condition is reached for said predetermined finite period of time; and
said inhibiting means includes a first normally open voltage responsive switch which closes the field current line to said alternator when said output is produced by said sensing means.
6. A system as in claim 5, wherein said inhibiting means also includes a second normally open voltage responsive switch which is connected to respond to said output of said sensing means to hold both said voltage responsive switches closed until said switching means disconnects said primary source.
7. A method of delaying loading of an internal combustion engine caused by a mechanically connected alternator including the steps of:
opening the field winding circuit of said alternator;
starting said engine;
sensing the operational condition of said engine immediately after said engine is started; and
closing the field winding circuit of said alternator when the operational condition of said engine is sensed to be above a predetermined level for a predetermined period of time.
8. A method as in claim 7, wherein said step of closing said field winding circuit of said alternator is performed at least until said engine is stopped.
Description
BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to the field of charging circuits for internal combustion engines and more specifically to the area of load control of engines during start up.

2. Description of the Prior Art

It has been found that on smaller internal combustion engines (four or less cylinders) an initial problem exists during start-up when the engine is cold. During initial ignition, an electrical start motor is energized from a power source, such as a battery, and is mechanically engaged to start the engine. Once the engine is started, the starter motor is disengaged and the engine enters a transition phase wherein it increases its running speed to a preset idle speed. The alternator, which is mechanically connected to the engine, is synchronously driven therewith and provides an output current that is used to recharge the battery and to supply current to other electrical loads that are turned on. The battery is normally at its lowest charge level immediately after start-up of the engine. Accordingly, heavy current is supplied by the alternator to charge the battery during the transition phase. In many instances, the heavy loading by the alternator during the transition phase causes the engine to be overloaded and stalling results. The most common means of preventing such stalling is to increase the fuel/air mixture to the engine; this results in increased fuel consumption and exhaust emissions.

SUMMARY OF THE INVENTION

The present invention is intended to overcome the problems in the prior art by providing a method and system by which alternator loading of the engine is inhibited during the initial start-up of the engine, until such time as the engine reaches a predetermined operational level and for a predetermined time period after it reaches that level. As a result, the initial start-up of a cold engine is facilitated since the alternator does not present any loads to the engine during the transition phase and is prevented from doing so until the engine has reached a cold idle level and has held that level for a predetermined amount of time. Subsequently, after the engine has maintained its operational level for a predetermined period of time, the alternator is electrically enabled through an associated voltage regulator to operate in a normal fashion and take over the electrical loads from the battery.

It is, therefore, an object of the present invention to provide a control system that electrically inhibits mechanical loading by the alternator of an engine during its transition phase.

It is another object of the present invention to provide a control system which delays recharge of a primary supply battery until after the associated internal combustion engine is allowed to run and stabilize.

It is a further object of the present invention to provide a relatively inexpensive means of solving the aforementioned problems.

BRIEF DESCRIPTION OF THE DRAWING

The FIGURE is an electrical schematic of a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is shown as being incorporated within a conventional charging system for an internal combustion engine, which includes an alternator 10; a voltage regulator 18; a battery 20; an ignition switch 26; a start motor relay K2; and a starter motor 30.

The alternator 10 includes a rotatable field winding 14, which is mechanically driven by the engine (not shown) and has end terminals respectively electrically connected through associated slip rings to ground and the F terminal of the voltage regulator 18. The alternator 10 further includes stator windings 12 (illustrated in a "Y" configuration) to provide three phases of alternating current to three pairs of rectifying diodes 16. The center connection of the stator windings 12 is connected to the S terminal of the voltage regulator 18. The diodes 16 provide rectification for the three phase AC generated by the stator windings 12 and provide a DC output to supply the required current. The A+ line is connected between a corresponding terminal on the voltage regulator 18 and the A+ terminal of the alternator 10. The A+ terminal on the alternator 10 is also connected to the positive terminal of the battery 20 which is the primary DC voltage source for the associated engine and vehicle. The battery 20 provides the necessary electrical energy to drive the starter motor 30 and also provides electrical energy to the ignition and energized accessory loads of the vehicle when the alternator 10 is faulty or otherwise inhibited. The purpose of the alternator 10 is to provide a voltage output which is higher than the primary source battery voltage so as to charge the battery and to provide sufficient power to handle the electrical load of the vehicle while the associated engine is running.

An ignition switch 26 is shown as a double pole triple throw (DPTT) switch wherein both poles 26a and 26b switch between a first (OFF) position, a second (RUN) position and a third (START) position. While it is true that ignition switches on many vehicles also include separate "ACCESSORY" and "LOCK" positions, those positions are not shown in the FIGURE, since they are not critical to the understanding of the present invention.

The pole terminal of switch 26a is connected to the positive terminal of the battery 20. The second and third terminals are shorted together and connected to the ignition system for the associated engine (not shown). The pole terminal of switch 26b is also connected to the positive terminal of battery 20. The second terminal of 26b is connected to the accessory load and voltage regulator circuit; and the third terminal is connected to a start motor relay coil K2.

The start motor relay coil K2, when energized, closes normally open contacts K2a and electrically connects the starter motor 30 to the positive terminal of the battery 20.

A voltage regulator 18 is conventional, in that it monitors the A+ voltage and accordingly controls the amount of field winding current to maintain the battery voltage at a predetermined level.

In the shown embodiment, a normally open set of relay contacts K1a are interposed in the field line. The contacts are controlled by relay coil K1, which is connected to one side of an actuation and holding circuit. The actuation and holding circuit includes a time delay close (TDC) vacuum switch 28 in parallel with a set of normally open relay holding contacts K1b, controlled by the relay coil K1. The parallel connected elements (K1b and 28) are connected between the second terminal of the ignition switch 26b and the relay coil K1.

During the OFF state of the associated internal combustion engine, the system is as depicted in the FIGURE. However, when the ignition switch is changed to the third position, energy from the battery 20 is supplied through switch 26b to energize the start motor relay K2. The start motor relay K2 closes normally open contacts K2a and voltage from the battery 20 is thereby connected to the starter motor 30, which in turn drives the associated internal combustion engine. D.C. energy is supplied through switch 26a to the ignition system for the associated engine. During this period of time, the field winding circuit of the alternator 10 remains open so that no current is generated by the alternator 10. Therefore, the alternator 10 produces minimal mechanical loading to the internal combustion engine.

After the engine has started, the ignition switch is returned to the second position, thereby deactivating the start motor relay K2 ; opening the associated contacts K2a ; and disengaging starter motor 30. In the RUN state, the switch 26b connects the alternator warning lamp 22 to the battery + line, and switch 26a continues to provide battery current to the ignition system.

The alternator 10 remains deactivated until such time as the vacuum within the engine reaches a predetermined level. For example, where an engine is structured so as to not exceed 3" Hg (10 KPa) vacuum during start motor cranking, the TDC vacuum switch 28 may be selected to close after a finite time period of approximately 5 seconds after the engine reached 10" Hg (34 KPa) vacuum. The TDC vacuum switch 28 therefore provides sufficient time for the engine to not only reach a predetermined operational level (10" Hg vacuum) but to be maintained at that level for a predetermined finite period of time (5 seconds). Such a period thereby ensures that the engine is out of its transition phase before allowing the engine to be loaded. At the end of the 5 second delay, after the engine reaches the predetermined operational level, the TDC vacuum switch 28 closes and energizes relay coil K1. Thereupon, the relay contacts K1a close and allow the voltage regulator 18 to energize the field winding 14, of the alternator 10. Thereafter, alternator 10 functions in a normal manner to supply current to the partially depleted battery 20 and to any other energized electrical loads within the vehicle.

When the relay coil K1 is energized, it also closes relay contacts K1b to provide a holding current to the coil K1, in the event the vacuum of the engine subsequently drops below the predetermined level and causes the switch 28 to open. The relay coil K1 will thereby remain energized until such time as the ignition switch 26b is changed from the second position to either the first or third positions.

It will be apparent that many modifications and variations may be implemented without departing from the scope of the novel concept of this invention. Therefore, it is intended by the appended claims to cover all such modifications and variations which fall within the true spirit and scope of the invention.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1993070 *Aug 22, 1932Mar 5, 1935Schwarze Electric CompanyAutomobile control system
US2111971 *Sep 12, 1936Mar 22, 1938Eclipse Machine CoAutomatic starter control for internal combustion engines
US2924722 *Jun 2, 1958Feb 9, 1960Roy T HardingVacuum control device for generators
US3270208 *Sep 5, 1963Aug 30, 1966Gen Motors CorpMotor vehicle electrical load control and starting system
US3714541 *Apr 19, 1971Jan 30, 1973Hitachi LtdVoltage control apparatus for ac generators
US3745442 *Apr 17, 1972Jul 10, 1973Syncro CorpVoltage and frequency responsive regulating circuit for a pm generator
US3767932 *Sep 1, 1972Oct 23, 1973C BaileyRemote vehicle starting system
US3878400 *Apr 30, 1973Apr 15, 1975Gen ElectricExcitation control arrangement for diesel-electric propulsion systems
US3904948 *Nov 18, 1974Sep 9, 1975Earle John LSource sensing battery charger
US4015187 *Oct 4, 1974Mar 29, 1977Hitachi, Ltd.Exciter arrangement for generators
US4035712 *Mar 5, 1976Jul 12, 1977Lucas Industries LimitedElectrical generating apparatus
US4146264 *Mar 2, 1978Mar 27, 1979Louis Michael GlickLoad control for wind-driven electric generators
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4629968 *Aug 23, 1985Dec 16, 1986General Motors CorporationAlternator load control system
US4659977 *Oct 1, 1984Apr 21, 1987Chrysler Motors CorporationMicrocomputer controlled electronic alternator for vehicles
US5075616 *Sep 29, 1989Dec 24, 1991Aisin Seiki Kabushiki KaishaEngine generator apparatus and method of operating same
US5144220 *Nov 27, 1990Sep 1, 1992Mitsubishi Denki K.K.Vehicle ac generator control system
US5352929 *Jun 25, 1993Oct 4, 1994Robert Bosch GmbhApparatus and method for regulating a generator of an internal combustion engine
US5352971 *Mar 11, 1993Oct 4, 1994Mitsubishi Denki Kabushiki KaishaElectronic control apparatus for a vehicle
US5977646 *Nov 26, 1997Nov 2, 1999Thermo King CorporationMethod for automatically stopping and restarting an engine powered generator
US5977647 *Nov 26, 1997Nov 2, 1999Thermo King CorporationAutomatic pretrip for engine powered generator
US6825576 *Jun 18, 2002Nov 30, 2004Dana CorporationMethod and apparatus for preventing stall in a starter/alternator equipped I.C. engine system
US7868592Dec 10, 2007Jan 11, 2011Visteon Global Technologies, Inc.Method of automotive electrical bus management
US8237305Jul 22, 2009Aug 7, 2012Alexander KadeAuxiliary electrical power system for vehicular fuel economy improvement
US20100019570 *Jul 22, 2009Jan 28, 2010Alexander KadeAuxiliary electrical power system for vehicular fuel economy improvement
CN102454527A *Oct 14, 2011May 16, 2012福特环球技术公司Methods and systems for engine starting
CN102454527B *Oct 14, 2011Oct 19, 2016福特环球技术公司发动机起动系统及车辆系统
DE3635957A1 *Oct 22, 1986Jul 2, 1987Mitsubishi Electric CorpSteuervorrichtung fuer einen an einem fahrzeug befestigten wechselstromgenerator
DE4222072C1 *Jul 4, 1992Mar 3, 1994Bosch Gmbh RobertEinrichtung zur Regelung der Ausgangsspannung eines von einer Brennkraftmaschine angetriebenen Generators
DE4325505A1 *Jul 29, 1993Feb 3, 1994Mitsubishi Electric CorpElectronic control device for automobile engine speed and dynamo - detects electrical load current gradient to reduce energising winding current for maintaining stable engine idling revs
DE4325505C2 *Jul 29, 1993Apr 19, 2001Mitsubishi Electric CorpElektronische Steuervorrichtung zum Steuern einer Lichtmaschine und der Leerlaufdrehzahl eines Motors eines Kraftfahrzeuges
DE102006032799B4 *Jul 14, 2006May 16, 2012Denso CorporationRotierende elektrische Maschine in Tandemanordnung für Fahrzeuge
Classifications
U.S. Classification322/10, 290/40.00R, 322/69
International ClassificationF02N11/08, H02P9/14, F02N11/00, F02D29/06
Cooperative ClassificationF02N11/0848
European ClassificationF02N11/08D
Legal Events
DateCodeEventDescription
Apr 1, 1982ASAssignment
Owner name: FORD MOTOR COMPANY,THE, DEARBORN, MICH, A CORP. OF
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:WINELAND, RICHARD J.;GAULT, ROBERT L.;REEL/FRAME:003959/0051
Effective date: 19811210
Jan 29, 1988FPAYFee payment
Year of fee payment: 4
Jan 29, 1988SULPSurcharge for late payment
Jan 27, 1992FPAYFee payment
Year of fee payment: 8
Nov 22, 1995FPAYFee payment
Year of fee payment: 12